Method of vaporizing



Jan- 19, 1960 J. H. HOLTHER METHOD oF vAPoRIzING Filed July 1l, 1956Am/56. Afan/5e,

IN VEN TOR.

United States Patent O 2,921,832 METHOD F vAPoRIzlNG James n. neither,santa Am, Calif. Application July 11, 1956, serial No. 597,138

z claims. `(c1. z1s3) A portable apparatus of this type is commonly indomestic use` and is provided with various interchange able attachmentsfor utilizing the discharged air stream for various specific purposes.For example, one attachment may be used as a nozzle to create an air jetto dislodge dust from inaccessible crevices. Another attachment may be ahair drier.

The general object of the present invention is to provide an accessoryinterchangeable'with such attachments for increasing the utility of theapparatus by making possible the additional function of effectivelydiffusing a bacteria-inhibiting agent into the atmosphere.

The invention is specifically directed to the problem of diffusingtriethylene glycol into the atmosphere to such extent as to decisivelyinhibit bacteria growth on dust particles oating in'lthe atmosphere.Heretofore, an attempt has been made to solve this problem by wetting apervious' member with triethylene glycol and exposing the member to theairs'tream discharged from the blower apparatus. This procedure has theadvantage of insuring that the triethylene glycol is thoroughlyvaporized, but it' has the fatal defect of being inherently incapable ofreleasing the chemical at an adequate rate to sterilize a room space ofeven moderate volume.

It has been suggested heretofore that an aqueous solution be sprayed orotherwise introduced into the air stream in finely divided liquid form,but it has been found that a temperature of the order of magnitude of110 F. or higher is required for adequate vaporization, and someprovision must be made, no t only to generate the 'required heat, butalso to permit effective transfer of the heat to the linelywdividedliquid agent.-

The present invention solves the problem without the addition of anyspecial heating means whatsoever, and does so by taking advantageof thefact that, when such an air stream discharged from a blower is retardedby a relatively fine mesh screen, or other suitable means, a zone ofrelatively high temperature is created, the heat being theiheat ofcompression ofthe air. The complete solution to the problem consists infirst restricting the discharged air stream to create-a low pressurezone for the introduction of the Vliquid agent into the air stream bysuction, and then retarding the air stream for the dual purpose ofproviding the highw temperature zone and of keepingthe finely dividedchemical or liquid entrained in 2,921,832 Patented Jan. 19, 1960 passagemember to create a local increase in velocity and corresponding localreduction of pressure. A reservoir 1s united with the passage means forholding a supply of the liquid solution and a fluid duct of small crosssection extends from the reservoir to the region of the restriction forfeeding the liquid agent into the air stream. Finally, means such as aline mesh screen is provided to resist the discharge of air from thepassage means for the purpose of creating the required high temperaturezone.

The preferred practice of the invention is further characterized by themounting of an annular solution reservoir around the passage means to besupported thereby, and the use of transparent or semitransparent plasticmaterial for fabricating both the reservoir and the passage means. Suchan arrangement makes the interior lof the passage means, as well as theinterior of the reservoir, visible for observation during the vapozingoperation.

The features and advantages of the invention will be apparent from thefollowing detailed description considered with the accompanying drawing.

In the drawing, which is to be regarded as merely illustrative:

Fig. l is a longitudinal, sectional View of the presently preferredembodiment of the invention; and

Fig. 2 is a fragmentary plan View.

The embodiment of the invention shown in Fig. 1 is interchangeable withattachments that are commonly used on a portable air circulatingapparatus in com.

munication with the outlet thereof. Fig. l shows a tubular portion 10 ofsuch an apparatus that forms its discharge outlet, the tubular portionbeing provided with three peripheral lugs 12 for cooperation withcorresponding bayonet slots of the attachments.

The particular embodiment of the invention shown in Fig. l comprises apassage member 14 having an eng. larged lower end portion 15 that formsan internal cirthe tubular portion 10 in such a manner as to cause thethe heated air for a sufficient-time interval for effective heattransfer and complete vapor-ization of the liquid agent.

The presently preferred embodiment of the invention comprises a passagemember for communication with the outlet of the blower apparatus with arestriction in the edge or rim 22 of the tubular portion 10 to compressthe ring 18 against the shoulder 16 in a sealing manner.

The passage member 14 discharges into the atmosphere and has arestricted portion for local increase in the lvelocity of the air streamtherethrough with consequent local drop in the static pressure of theair stream. For this purpose, the passage member 14 may be ofsubstantially uniform tubular conguration with a restrictingmember 24mounted therein to form a restricting throat for the creation of a looallow pressure region. In the construction shown, the restricting member24 is a ringshaped member of the configuration shown that is suitablybonded in place.

vA small Huid duct or tube 25 terminates in the lowy pressure regioninside the venturi ring 24 to supply the liquid agent solution to theair stream and to serve as a discharge nozzle for the liquid agent. Thissupply tube 25 for the liquid agent may be placed in communication'.V`with a' body of the .liquid agent inany suitable manner, arid'preferablywill be'provided with an adjustment Valve d to vary the rate of flow ofthe liquid agent therethrough.

In this particular embodiment of the invention, the tube 25 is incommunication with a supply reservoir 26 of annular configuration thatencircles the tubular portion 10 and is united therewith for supportthereby. The

reservoir 26 has an annular bottom Wall 28, a cylindricalV peripheralwall 30, and an annular top wall 32. The

top wall 32v isprovided with a. convenient iill. opening that isnormally closed by a removable plug 34.

In the construction shown, the tube 25 for discharging the liquid agentinto the venturi throatextends through the Wall of the tubular passagemember 14 from a valve body 35 that has a manually adjustable needlevalve member 36. A second similar small tube 38 extendsv small streams,and, for this purpose, may be a perforatev Screens of 20 to.

member such as a screen or the like. 120 mesh have been found acceptablefor this purpose, the test for acceptance being whether or not provisionof such a ow-retarding means causes the temperature of lthe air streamto be of a minimum of the order of magnitude of 110 F. Apparently, thistemperature of the air stream between the venturi member 24 and thescreen 40` is derived from the heat of compression generated# intheblower apparatus. The screen 40 may be a'wire cloth disk clamped betweenthe rim of the passage member 14 and a retaining ring 42, the retainingring being removably mounted on the rim bymeans of small screws 44.

Preferably, the device, including the passage member 14 and thereservoir 26, is made of transparent or semitransparent plastic materialto make visible not only the interior of the reservoir, but also to makevisible the interior of the passage member 14. The valvebody 35comprises a triangular block of such plastic material with a suitablebore therethrough throttled by the valve member 36.

The manner in which the device serves its purpose may be readilyunderstood from the foregoing description.

AA suitable liquid agentis placed inthe reservoir 26, for

example a solution of one part triethylene glycol to approximately l ormore parts of water. mounted on the blower outlet by the describedbayonet connection and the portable blower is energized to force astream of air through the passage member 14. The reduction in pressurein the region of the Venturi throat member 24 causes a pressurediiferential between the interior of the reservoir 26 and the interiorof the passage member to cause the liquid agent to flow through the.

tubes 38 and 25 for discharge into the air stream.

The air stream contains substantial heat of compression generated by theblower, and the provision of the screen 40 retards the air stream in amanner to conserve the heat of compression to the extent, at least, ofmaintaining a temperature of approximately 110 F. on the upstream sideof the screen 40. The screen 40 is positioned far enough away from theliquid supply tube 25 and the venturi throat member 24 to provide a timeAinterval in the heated portion of the air stream to permit suficientheat transfer from the air stream to the finely divided liquid agent tocause the desired vaporization of the liquid agent at the desired rate.As a result, a sufficient quantity of the triethylene glycol isevaporated into the heated air stream to result in the atmosphere ofthesurrounding room space reaching a concentration of at leastone part oftriethylene glycol to four hundred million parts of atmosphere. Thisconcentration is sucient to inhibit bacteriological .growth on dust `inthe The device is 4 atmosphere. Since the liquid agent shouldbe'uniformly distributed throughout the atmosphere, the blower ap.paratus should run for a substantial period of time with the feed of theliquid agent retarded by the needle valve member 36 suticient forcontinuous dispensation throughout the prolonged time period.

If the temperature of they airstream on the upstream side of the screen4,1)V is not relatively highthe triethylene glycol precipitates and thusdefeats itsvpurpose. The minimum temperature varieswithV the humidity,and, for average humidity,4 should 4been the orderof 110 F. The use ofan -mesh screen 40 with a typical'portable blower-type aircirculatingapparatus has been found to result in a temperature on theorder of 120- F. in the heat-transfer region of the passage member.

Final vaporization is accomplished by the flashing of the finely dividedliquid;l particles as they" escape from the screen into the lowerpressure, ofthe; atmosphere.

My description in detail of the; selectedembodiment of the inventionwill suggest various changes, substitutions and other departuresy frommydisclosure that properly lie within the Vspirit and scope of theappended claims.

Having described my invention,v I claim:

`l. A method of introducing a vapor ofa volatile liquid into a roomspace, characterized bythe use of a recirculating compressing blowermeans for discharging a stream of air into the. room space, saidvmethodincluding the steps of: confining said discharge stream of air in aregion and providing numerous small 'openings for restricted release ofthe air stream -fromf the region into the atmosphere of the roomthereby. to provide resistance to'discharge of air from theregion tomaintain the pres,- sure yof the air stream in the Vregiongaboveatmospheric pressure for conserving the heat ofpcompression of the airstream to maintaina temperature ofV at least F. in the region;Vrestricting thestream in said region at an intermediatezoneof theregion to provide a local low pressure in said zone; and introducingsaidy liquid into said low pressure zone to cause the liquid to beentrained by the -air stream whereby heat yis transferred from the airstream in said region to lthe liquid for vaporization of at least aportion lof the entrained liquid in said region. y k

2. A method as set forth lin ,claimV l in which said' liquid is fed intosaid low pressure `zone at a rate for vaporization of a portion of theVliquid in said region by `heat transfer theretoand vaporization of anadditional portion by flashing action outside said region immediatelydownstream from said restricted openings.'

References Cited intheleof thisA vpatent UNITED STATES PATENTS OTHER'REFERENQEs VChemical Engineers HalltlDQOlr 10h11 Perry, 3rd ed.,McGraw-Hill, pp. 40G-401,.

1. A METHOD OF INTRODUCING A VAPOR OF A VOLATILE LIQUID INTO A ROOMSPACE, CHARACTERIZED BY THE USE OF A RECIRCULATING COMPRESSING BLOWERMEANS FOR DISCHARGING A STREAM OF AIR INTO THE ROOM SPACE, SAID METHODINCLUDING THE STEPS OF: CONFINING SAID DISCHARGE STREAM OF AIR IN AREGION AND PROVIDING NUMEROUS SMALL OPENINGS FOR RESTRICTED RELEASE OFTHE AIR STREAM FROM THE REGION INTO THE ARMOSPHERE OF THE ROOM THEREBYTO PROVIDE RESISTANCE TO DISCHARGE OF AIR FROM THE REGION TO MAINTAINTHE PRESSURE OF THE AIR STREAM IN THE REGION ABOVE ATMOSPHERIC PRESSUREFOR CONSERVING THE HEAT OF COMPRESSION OF THE AIR STREAM TO MAINTAIN ATEMPERATURE OF AT LEAST 110* F. IN THE REGION, RESTRICTING THE AIRSTREAM IN SAID REGION